Splines

AutoGrid—Lets you automatically create objects on the surface of other objects by generating and activating a temporary construction plane based on normals of the face that you click.

For more information, see AutoGrid.

Start New Shape—A shape can contain a single spline or it can be a compound shape containing multiple splines. You control how many splines are in a shape using the Start New Shape button and check box on the Object Type rollout. The check box next to the Start New Shape button determines when new shapes are created. When the box is on, the program creates a new shape object for every spline you create. When the box is off, splines are added to the current shape until you click the Start New Shape button.

Shape Selection buttons—Let you specify the type of shape to create.

Lets you name an object and assign it a viewport color. For details, see Name and Color rollout.

Lets you turn on and off the renderability of the spline, specify its thickness in the rendered scene, and apply mapping coordinates.

You can animate render parameters, such as the number of sides.

You can also convert the displayed mesh into a mesh object by applying an Edit Mesh modifier or converting to an Editable Mesh. The system will use the Viewport settings for this mesh conversion if Use Viewport Settings is checked; otherwise it will use the Renderer settings. This gives maximum flexibility, and will always give the conversion of the mesh displayed in the viewports.

Viewport—Choose to set viewport thickness, sides, and angles. Available only when Use Viewport Settings is turned on.

Renderer—Choose to set renderer thickness, sides, and angles.

Thickness—Specifies the diameter of the viewport or rendered spline. (Spinner value: float, 0.0 to 1.0E30)

Splines rendered at thickness of 1.0 and 5.0, respectively

Sides—Sets the number of sides for the spline mesh in the viewports or renderer. For example, a value of 4 will give you a square cross section.

Angle—Adjusts the rotational position of the cross-section in the viewports or renderer. For example, if you have a square cross section you can use Angle to position a "flat" side down.

Renderable—When on, the shape is rendered using the specified parameters.

Generate Mapping Coords—Turn this on to apply mapping coordinates. The U coordinate wraps once around the thickness of the spline; the V coordinate is mapped once along the length of the spline. Tiling is achieved using the tiling parameters in the material itself.

Display Render Mesh—Displays the mesh generated by the spline.

Use Viewport Settings—Lets you set different rendering parameters for the viewports and displays the mesh generated by the Viewport settings. Available only when Display Render Mesh is turned on.

These settings control how a spline is generated. All spline curves are divided into small straight lines that approximate the true curve. The number of divisions between each vertex on the spline are called steps. The more steps used, the smoother the curve appears.

Steps—Spline steps can be either adaptive (that is, set automatically by turning on Adaptive) or specified manually.

When Adaptive is off, use the Steps field/spinner to set the number of divisions between each vertex. Splines with tight curves require many steps to look smooth while gentle curves require fewer steps. Range=0 to 100.

Optimize—When on, removes unneeded steps from straight segments in the spline. Optimize is not available when Adaptive is on. Default=on.

Adaptive—When off, enables manual interpolation control using Optimize and Steps. Default=off.

When on, Adaptive sets the number of steps for each spline to produce a smooth curve. Straight segments always receive 0 steps.

Optimized spline left and adaptive spline right. Resulting wireframe view of each, respectively, on the right.

Many spline tools use the Creation Methods rollout. On this rollout you choose to define splines by either their center point or their diagonal.

Edge—Your first mouse press defines a point on the side or at a corner of the shape and you drag a diameter or the diagonal corner.

Center—Your first mouse press defines the center of the shape and you drag a radius or corner point.

Text and Star do not have a Creation Methods rollout.

Line and Arc have unique Creation Methods rollouts that are discussed in their respective topics.

You can create most splines using keyboard entry. The process is generally the same for all splines and the parameters are found under the Keyboard Entry rollout. Keyboard entry varies primarily in the number of optional parameters. The image above shows a sample Keyboard Entry rollout for the Circle shape.

The Keyboard Entry rollout contains three fields for the X, Y, and Z coordinates of the initial creation point, plus a variable number of parameters to complete the spline. Enter values in each field and click the Create button to create the spline.